Radio communication provides for information to be modulated onto channels corresponding to carrier frequencies of the radio frequency band. Such information is then transmitted and received on the channels by radios that are within communication range of each other. This communication range can be extended by using what is commonly known as repeaters to receive and re-transmit the information to other radios. When radios communicate via a repeater, a transmitting radio transmits information on a channel to the repeater. The repeater receives this information and then re-transmits the information to other radios on a different channel.
A repeater cannot be use when radios are not within communication range of the repeater or when channels used by the repeater are not available for relaying information by receiving and re-transmitting. When the repeater cannot be used for relaying information, direct communication between radios may still be possible. However, such radios need to be within communication range of each other. Direct communication without using repeaters is known in the art as talkaround.
In U.S. Pat. No. 5,423,055, a radio system is described in which multiple talkarounds are controlled by a system controller based on geographical distances between radios. In the multiple talkarounds described in U.S. Pat. No. 5,423,055, users need to manually activate a switch on a radio to enable the radio to communicate directly with other radios using one or more talkaround channels. This can be a problem as the users will then have to determine when talkaround channels are required and may forget to switch back to using repeater channels after talkaround. Incorrectly determining use of the talkaround channels or forgetting to switch to using the repeater channels after talkaround typically cause communication failure. Furthermore, conventional radio systems require use of system resources for determining possibility of talkaround before enabling radios to do so. Such determining puts additional demands on the system resources which can otherwise be used elsewhere in a radio system.
Therefore, it is desirable to overcome or at least alleviate at least one of the problems associated with channel selection for radio communication systems supportable with repeaters.